How to reset OpenGl for Solid lighting?
You can print the current settings to a console with a simple script:

import bpy

def round_vec3(vec): return tuple(map(lambda c: round(c, 3), vec))

solid_lights = bpy.context.user_preferences.system.solid_lights

for i, light in enumerate(solid_lights):
    print()
    print("Light %i:" % i)
    print("  Use:", light.use)
    print("  Direction:", round_vec3(light.direction))
    print("  Diffuse Color:", round_vec3(light.diffuse_color))
    print("  Specular Color:", round_vec3(light.specular_color))


Based on the settings for solid lights in startup.blend, here's a script to reset your current settings to the defaults:

import bpy

lights = [
    {
        'use': True,
        'direction': (-0.892, 0.3, 0.9),
        'diffuse_color': (0.8, 0.8, 0.8),
        'specular_color': (0.5, 0.5, 0.5)
    },
    {
        'use': True,
        'direction': (0.588, 0.46, 0.248),
        'diffuse_color': (0.498, 0.5, 0.6),
        'specular_color': (0.2, 0.2, 0.2)
    },
    {
        'use': True,
        'direction': (0.216, -0.392, -0.216),
        'diffuse_color': (0.798, 0.838, 1.0),
        'specular_color': (0.066, 0.0, 0.0)
    }
]

solid_lights = bpy.context.user_preferences.system.solid_lights

for s, l in zip(solid_lights, lights):
    for k, v in l.items():
        setattr(s, k, v)


If you don't want to deal with Python, just install this addon version of the script and click the Reset Solid Lights button in the User Preferences header (where the Save settings button is) while you are on the System tab:

bl_info = {
    "name": "Reset Solid Lights",
    "author": "CoDEmanX",
    "version": (1, 0),
    "blender": (2, 65, 0),
    "location": "User Preferences &gt; System",
    "description": "Reset OpenGL Solid Lights to factory defaults",
    "warning": "",
    "wiki_url": "",
    "category": "User Interface"}

import bpy
from bpy.types import Operator

# OpenGL solid lights settings like in factory startup.blend
lights = [
    {
        'use': True,
        'direction': (-0.892, 0.3, 0.9),
        'diffuse_color': (0.8, 0.8, 0.8),
        'specular_color': (0.5, 0.5, 0.5)
    },
    {
        'use': True,
        'direction': (0.588, 0.46, 0.248),
        'diffuse_color': (0.498, 0.5, 0.6),
        'specular_color': (0.2, 0.2, 0.2)
    },
    {
        'use': True,
        'direction': (0.216, -0.392, -0.216),
        'diffuse_color': (0.798, 0.838, 1.0),
        'specular_color': (0.066, 0.0, 0.0)
    }
]

class WM_OT_solid_lights_reset(Operator):
    __doc__ = bl_info["description"]
    bl_label = bl_info["name"]
    bl_idname = "wm.solid_lights_reset"
    bl_options = {'REGISTER'}

    def execute(self, context):

        solid_lights = bpy.context.user_preferences.system.solid_lights

        for s, l in zip(solid_lights, lights):
            for k, v in l.items():
                setattr(s, k, v)

        return {'FINISHED'}


# Add button to user pref header (conditionally)
def userpref_button(self, context):
    if context.user_preferences.active_section == 'SYSTEM':
        self.layout.operator(WM_OT_solid_lights_reset.bl_idname)


def register():
    bpy.utils.register_class(WM_OT_solid_lights_reset)
    bpy.types.USERPREF_HT_header.append(userpref_button)

def unregister():
    bpy.utils.unregister_class(WM_OT_solid_lights_reset)
    bpy.types.USERPREF_HT_header.remove(userpref_button)

if __name__ == "__main__":
    register()